PNDS / Marking codes / 1D

Identify an unknown SMD part: marking code “1D”

Packages rarely print the full part number. The marking below is shared by several part numbers — use the package, pin count and the manufacturer family together to narrow it down, then confirm against the datasheet.

25 candidates 20 with manufacturer source-traceable

Candidate part numbers

Part number	Manufacturer	Package	Mapping source
BC846	PHI	SOT-23	Public marking directory
BC846W	NXP	SOT-323 16ta - 3a PhH	Public marking directory
BU4344F	ROHM ^*	SOP-4	Public marking directory
BU4344FWE	ROHM ^*	VSOF-5	Public marking directory
BU4344G	ROHM ^*	SSOP-5	Public marking directory
IRLML5103	IR	SOT-23	Public marking directory
KST42	FSC	SOT-23	Public marking directory
MA2J113	PANASONIC ^*	SOT-346	Public marking directory
MM5Z56V	FSC	SOD-523	Public marking directory
MMBTA42	KEC AMERICA (USD)	SOT-23	Public marking directory
MMBTA43	MCC	SOT-23	Public marking directory
R3111N311A	RICOH ^*	SOT-23-5	Public marking directory
RH5RL41AA	RICOH ^*	SOT-89	Public marking directory
RN5RL41AA	RICOH ^*	SOT-23-5	Public marking directory
RN5VD31CA	RICOH ^*	SOT-23-5	Public marking directory
RQ5RW17BA	RICOH ^*	SOT-143R	Public marking directory
SMBTA20	SIEMENS	SOT-23 16ta - 3g Vs	Public marking directory
SMBTA42	INFINEON	SOT-23 16ta - 3a Inf	Public marking directory
SXTA42	INFINEON	SOT-89	Public marking directory
TMPTA42	VISHAY SPRAGUE	SOT-23	Public marking directory
MBTA42	—	SOT-23	Public marking directory
MM3Z2V7	—	SOD-323	Public marking directory
MM3Z56V	—	SOD-323	Public marking directory
MMBTA42L	—	SOT-23	Public marking directory
R1161D311A	—	—	Public marking directory

How we narrow this down

Package first — SOT-23 vs SOD-123 vs SC-59 eliminates most candidates immediately.
Pin count and body size — a 3-pin SOT-23 LDO cannot be a 6-pin dual transistor.
Marking style — laser-marked parts are usually newer production; ink marking often indicates older or second-source vendors.
Circuits around it — a part sitting on a rail with an inductor is a regulator, not a diode.
Datasheet check — every credible candidate lists its marking scheme in the “marking information” section.

FAQ

Same code, several parts — which one do I actually have? Compare package + pin count + surrounding circuit; if it still fits two parts, request a sample verification before production.
Can I substitute between the candidates? No — the same marking may sit on electrically different parts. Always match the electrical spec sheet, not just the marking.
Where do these mappings come from? Public SMD marking directories and historical stock tables; each row keeps its source so you can trace it.

Other codes starting with “1”

10 11 12 13 14 15 16 18 1A 1B

Still not sure what the part is?

Send the code, package and a photo through the BOM hub — our engineers cross-check it against datasheets and sourcing records.

How these mappings are compiled: public SMD marking directories plus our own stock records. Each row keeps its original reference internally, so any mapping can be traced on request. ^* Manufacturer derived from the part-number family (some directory entries carry no manufacturer) — treat it as a lead, not a datasheet fact. Markings are indicative only — confirm with the physical batch marking and the original datasheet before ordering.